GB696677A - Improvements in and relating to prismatic reflectors and means for producing them - Google Patents

Abstract

696,677. Reflex lights. FAIRYLITES, Ltd., and WILSON, H. F. March 21, 1951 [April 22, 1950], No. 9968/50. Class 97 (i). [Also in Group V] A reflex reflector as of glass or synthetic resin is of the kind having an inner cluster of contiguous right-angled triple reflector elements in the form of tetrahedra with all three base vertices of each tetrahedron removed and an outer series of such elements in the form of tetrahedra with the inner base vertex or vertices of each tetrahedron removed and contiguous with the outer elements of said cluster and made from a mould having a group of dual-facet mould elements, a marginal series of mould elements and triads of single facet mould elements which triads are of hexagonal cross-section and are arranged in corresponding apertures formed by the other mould elements, and is characterized in that the centres of the triple reflector elements moulded from said triads lie on a diamond outline or on two or more diamond outlines disposed one within the other, the sides of the or each diamond outline being parallel to four sides of a hexagon on which lie the outer edges of the reflector elements formed by the single facet elements of the marginal series, and in that each triple reflector element moulded from a triad is surrounded by and contiguous with six other triple reflectors except for those moulded by triads and lying nearest the remaining two sides of the hexagon where five triple reflector elements only surround and are contiguous with the central one whereby said inner cluster and said outer series of triple reflector elements are confined to the hexagon. The mould shown in Fig. 1, is built up of dualfacet elements Bx, Cx and single facet elements Dx, Ex and Fx obtained from a rod of diamond section. Nineteen elements Cx form four hexagonal apertures each centred on a corner of a diamond outline A and in each aperture is seated a triad of elements Ex. Ten elements Cx, eighteen elements Bx and eight elements Ex form another ten hexagonal apertures, each centred at a corner or on a side of a second diamond outline B, a triad of elements Ex being seated in each aperture. Eight elements Dx and four elements Fx complete the mould. The reflector produced by this mould is shown in Fig. 8, and includes three different types X, Y, Z of triple reflecting elements. There is an inner cluster of triple reflecting elements X, four centred on the corners of diamond outline A<SP>1 </SP>and ten centred on the corners and sides of outline B<SP>1</SP>. The outer series of triple reflector elements are made up of the elements Y and Z. Specification 532,672 is referred to.